Take a look at central vacuum pump motors. I have 1 on my 4' X 4' table and it hold sheet metal and polycarbonate down like nails. ShotBot folks use this type of hold down regularly. The only concern about your setup with just 1 square ft is that your surface area is really small for a low draw vacuum. On my table anything over 3 square ft is held down firmly and I can make virtually any cut to it. At 1 square ft and am not so sure? You may need something more along the lines of a real vacuum pump? I cheap test would be to try a shop vac, if that works then a central vac motor would is stronger than that.